The present invention relates to coating compositions that provide enhanced abrasion resistance and wear clarity, and methods for using the same. More specifically, the improved abrasion resistance and wear clarity is achieved by adding a combination of alumina and silica to a coating.
Floor coverings, such as wood and vinyl flooring, are subject to wear from foot traffic and contact with heavy objects. As such, abrasion resistance is a particularly desired property in a floor covering. Resistance to contamination or staining caused by a variety of sources is also desirable. To provide these desired characteristics, one or more layers of sealers and/or topcoats are typically applied to the flooring. For example, an abrasion resistant layer having hard particles that impart abrasion resistance can be applied. Often, when this layer and particles experience wear, a whitening or clouding of the layer occurs. Thus, abrasion resistant layers having improved wear clarity are desired.
The present invention is directed to coating compositions generally comprising a combination of alumina and silica. The alumina has been treated or modified with an organosilane, as further described herein; the silica can be modified or unmodified. The particles are typically dispersed in a coating material suitable for use with flooring.
It has been surprisingly discovered that use of the combination of particles described herein provides a coating having an abrasion resistance typically only seen with coatings in which much higher levels of particles are added. xe2x80x9cWear resistancexe2x80x9d and xe2x80x9cabrasion resistancexe2x80x9d, used interchangeably herein, refer to the ability of a material to resist displacement upon exposure to relative motion against hard particles or protuberances. Displacement is usually observed visually, as a removal of the coating material thereby exposing the underlying surface. Wear resistance can be determined through a variety of tests known in the art, such as a Taber abrasion test, a Gardner scrubber test, a falling sand test and the like. It has been further discovered that the present compositions have excellent wear clarity. That such wear clarity can be achieved without sacrificing abrasion resistance is a surprising result.
A number of advantages are offered by the present coatings. Because the weight percent of filler can be dramatically decreased, the coatings that result from the present compositions have much less haze than coatings having higher weight percents of particles. This clarity is maintained even as the layer wears. This is particularly relevant for wood floor coatings, in which visibility of the natural grain of the wood is desired. In addition, because less of the formulation is comprised of mineral particles, greater amounts of other performance enhancing components can be added to the coating. For example, more binder can be added to give the cured film enhanced gouge resistance, enhanced adhesion, and the like; more additives contributing to desirable wet coating properties, such as viscosity and flow characteristics, can also be added. All of this is accomplished without sacrificing the abrasion resistance of the coatings.